1. Field of the Invention
The present invention is directed to removable, nonslip, non-adhesive coverings which are used as shelf, drawer or storage liners. In particular, the covering sheet features an improved composite material having a top decorative layer of polymeric film combined to a continuous bottom layer of unsupported foam. The structure of the multilayered composite material facilitates the convenient hand tearing of the sheet to size through a grid of perforations oriented along the vertical and horizontal axes of the covering.
2. Description of the Prior Art
Shelf, drawer or storage liners have been extensively sold at retail venues and are available in a selection of self-adhesive or non-adhesive coverings. Printed wall coverings or papers were once used to protect the wooden interiors of cabinets or drawers from exposure to moisture. These permeable materials were eventually replaced with the application of decorative self-adhesive plastic sheets, which provide a greater degree of water resistance to the unfinished or varnished surfaces of cupboards. Self-adhesive shelf liners primarily consist of a facing layer of transparent, opaque or printed polymeric film coated with an underlying layer of pressure sensitive adhesive. The pressure sensitive adhesive may be combined with a siliconized release liner, which is removed prior to the application of the decorative plastic laminate. To assist the consumer in the installation of the product, the release liner typically features an imprinted grid of guide lines following the vertical and horizontal axes of the covering. The interior dimensions of cabinets or drawers are then transferred to the printed release liner prior to cutting the shelf liner to size.
Another provision known in the art includes a decorative laminate having a releasable first face with an adhesive coated reverse face, thereby permitting the sheet to be rolled upon itself and readily unrolled without the need for a separable siliconized liner. In one variation, the covering may consist of a polypropylene film having a fine pattern of micro-embossed indentations formed into the exterior facing of the sheet. The micro-embossed pattern reduces the surface area of the laminate and limits the corresponding degree of contact with the adhesive layer when wound into rolls for retail distribution. Alternatively, transparent varnishes containing an admixture of polymerized siloxanes, which are more commonly referred to as polysiloxanes, have been applied to create a releasable decorative layer for self-adhesive shelf liners made from paper or polymeric materials. Although the use of silicone coatings or micro-embossed indentations enhance the smooth separation of pressure sensitive laminates, the installation of such self-wound materials can be very troublesome in poorly accessed locations. The omission of a printed release liner eliminates the efficient means for preparing the self-adhesive covering to fit within the confined interiors of cabinets or drawers. Instead, it is necessary to first adhere the self-wound sheeting to an uncovered surface, while folding any remaining edge portions up along the adjacent walls of a cupboard, then subsequently trimming away the excess material with a razor blade.
In the prior art, the application of self-adhesive coverings are known to become frequently unmanageable. It is difficult to accurately achieve consistent straight cuts along the length and width of the material, even with the added convenience of an imprinted release liner, and especially when the shelf liner is self-wound. Irregular, oversized or non-conforming laminates that will not precisely adhere to their intended surfaces may result in the formation of entrapped air pockets beneath these impermeable coverings. Such air pockets eventually collapse under load, permanently causing unsightly creases and wrinkles Moreover, a further problem emerges when the exposed adherent layer inadvertently folds upon itself, as the separation of these mutually bonded surfaces results in the irreparable deformation of the polymeric film.
Previous attempts have been made in the prior art to simplify the alteration of self-adhesive shelf liners so that they may correspond to the dimensions of cabinets and drawers. For example, earlier methods include the provision of forming lines of weakness into a laminate sheet to facilitate the hand-tearing of the covering to fit a surface of predetermined size.
U.S. Pat. No. 6,238,762, issued on May 29, 2001 to R. Friedland et al., discloses a self-adhesive decorative covering adapted with through-cut microperforations and embossed prescores, which are oriented at right angles, to provide rectilinear yield lines enabling the manual hand sizing of a sheet. Lines of weakness may also run diagonally between the grid of microperforations to facilitate changes in the direction of tearing. The disclosure further includes a provision for extending the embossed prescores partially through the profile of the laminate. The arrangement of through-cut microperforations and embossed prescores may be used in combination with a self-adhesive covering having a separable release liner that includes a corresponding pattern of perforations or, alternatively, with a self wound sheet having a releasable polysiloxane facing.
U.S. Pat. Nos. 4,380,564 and 4,465,729, issued on Apr. 19, 1983 and Aug. 14, 1984, respectively, to Cancio et al., disclose a plastic laminate having an intersecting grid of tear lines formed into the surface of the sheet material whereby the film may be torn by hand in more than one direction. In a preferred embodiment presented in both patents, the plastic sheet materials are composed of a polymeric component consisting of a low density polyethylene having a disperse phase of calcium carbonate, with the preferred ratio of the foregoing ingredients contingent upon the dimension of the grid pattern embossed into the film. The inventors claim that the selected admixtures of polyethylene and calcium carbonate enhance the tear assisting provision of their polymeric sheet while maintaining the overall tensile strength characteristics of the material. In each disclosure, a layer of adhesive may be disposed on one side of the plastic covering, which is protected by a release liner that does not have any cross-tearable lines. Accordingly, installation of the materials taught in both patents first requires the removal of the release liner prior to hand tearing the laminate to size.
The primary disadvantage of the prior art, inherent within self-adhesive coverings which integrate perforated or cross-tearable features, concerns the inadvertent separation of the shelf liner along unselected lines of weakness, especially when attempting to pull apart mutually adhering surface portions that have accidentally folded upon themselves. The strong reciprocal bond created through such mishaps may surpass the tensile strength property of the yield lines, causing the unintended fragmentation of the plastic sheet, thereby rendering the covering unsuitable for installation. Moreover, another difficulty relates to the replacement of perforated or cross-tearable laminates after long-term use, as the molecular structure of the polymeric film degrades with age, while the self-adhesive coating becomes fully cured to the interior surfaces of cabinets or drawers. Consequently, the increased bond strength of the adhesive, combined with the embrittlement of the plastic, will result in the adverse disintegration of the material into miniscule pieces upon removal.
Although the use of self-adhesive coverings in the prior art have long provided consumers with the means to both decorate and protect shelving and drawers, the thin layer of polymeric film often fails to conceal uneven surface flaws or irregularities. More recently, the renovation or construction of kitchens and bathrooms now feature cabinets with water-resistant interior laminates, sold commercially under the Wilsonart® or Formica® brands, which are primarily manufactured from thermosetting plastic resins. Since the latest cabinet fabrications also use composite particle board materials, the application of such laminates inhibits moisture from coming into contact with the bonded wooden fibers and produces a smooth consistent surface that can be easily cleaned. Where functionality and durability is therefore enhanced, the thermoset resin permanently hardens under heat and pressure during the formation of these laminates, thereby increasing the rigidity while diminishing the impact resistance of the material. Without the benefit of a suitable protective covering, the striking force of ordinary household articles can cause pieces of the thermoset plastic sheet to break away from shelving or drawers. In view of the fact that self-adhesive coverings offer superficial protection against impact resistance, and their subsequent removal often leaves behind a viscous residue, non-adhesive shelf liners have gained widespread acceptance.
One type of non-adhesive shelf liner in the prior art consists of a knitted polyester scrim with a coating of thermally foamed polyvinyl chloride (PVC) resin. The knitted construction of the scrim provides an arrangement of woven yarns defining a pattern of apertures that correspond to a configuration of openings extending through the thickness of the cured PVC material. Alternatively, the PVC resin may be knife coated to both sides of a knitted scrim devoid of openings, or to a non-woven fabric of autogenously bonded polyester fibers, producing a solid continuous layer of supported foam. The PVC compound also includes a plasticizer that imparts a removable nonslip mechanical bond between the shelf liner and an applied surface. Such coverings provide a degree of protective cushioning and are often laminated or fused with a top decorative layer of plastic film. The basic deficiency of foamed non-adhesive liners is that they do not incorporate any provision for the consumer to conveniently alter the product to match the interior dimensions of cabinets or drawers. Moreover, the overall thickness of the shelf liner, along with the variable density of the knitted scrim and thermally cured foam, makes it difficult to maintain the uniform alignment of cuts along the length and width of the material.
Further, prior art methods—which are used to configure cross-tearable features within self-adhesive shelf liners—cannot be successfully applied to form lines of weakness in removable, nonslip, non-adhesive versions that are supported with a knitted scrim or non-woven fabric. The embossment of an intersecting grid of tear lines will not adequately diminish the tensile strength property of the woven yarns or bonded polyester fibers, where the perforation of a linear series of discontinuous holes will not effectively weaken adjacent segments of imperforated substrate. The adaptation of these coverings for hand tearing becomes even less viable with the added combination of a laminated or fused layer of decorative plastic film.
U.S. Pat. No. 5,707,903, issued on Jan. 13, 1998 to H. Schottenfeld, discloses a nonslip laminated liner comprising a foamed PVC coated scrim with a vinyl sheet covering. The scrim increases the tensile strength properties of the foamed nonslip pad, which includes a plurality of open cells extending through the thickness of the cured PVC material. Additionally, the vinyl sheet covering is permanently bonded to the top plane of the nonslip pad.
U.S. Pat. No. 5,854,144, issued on Dec. 29, 1998 to J. Hawley, describes a nonslip multilayer sheet material for covering household surfaces. The cushioned shelf liner is made by laminating a layer of thin plastic film to the top surface of a spunbonded non-woven polyester fabric. The bottom surface of the non-woven fabric is coated with a continuous layer of polyurethane foam.
U.S. Pat. Nos. 5,863,845 and 5,874,371, which respectively issued on Jan. 26, 1999 and Feb. 23, 1999 to T. Owen, similarly disclose a removable non-skid, non-adhesive surface covering comprising a woven substrate having a plurality of apertures, wherein at least a portion of the bottom surface of the substrate is coated with a PVC resin. Alternatively, a non-woven substrate may also be used. The application of the polymeric compound prevents the covering from skidding tangentially or laterally in a plane parallel to an applied surface. A decorative sheet is adhered to the top surface of the non-skid covering.
U.S. Pat. No. 6,022,617, issued on Feb. 8, 2000 to M. Calkins, discloses a laminated nonslip liner or mat having an intermediate layer of non-woven material printed on one side with a pattern of relatively high friction material. The imprinted pattern consists of a high density matrix of latex or PVC projections. A decorative vinyl sheet is laminated to the obverse side of the non-woven material. Similarly, U.S. Pat. No. 6,159,583, issued on Dec. 12, 2000 to the same inventor, discloses a laminated nonslip liner or mat comprising an interposing layer of non-woven material printed with a high density matrix of polyethylene projections. The imprinted thermoplastic resin provides non-adhering, non-marring contact with an underlying surface.
U.S. Pat. No. 6,221,796, issued on Apr. 24, 2001 to J. Hawley et al., describes a laminated shelf lining material having nonslip characteristics. The covering is produced by bonding a smooth continuous layer of vinyl film to a layer of scrim comprising woven threads surrounded by a foamed PVC plastic. Comparatively, U.S. Pat. No. 6,130,174, issued on Oct. 10, 2000 to the same inventor, discloses a smooth surfaced foam laminate and a method for making the material similar to the Hawley '796 patent.
U.S. Pat. No. 7,253,126, issued on Aug. 7, 2007 to W. Browne, discloses a decorative nonslip shelf liner that comprises a multi-layered thermoplastic composite sheet. A decorative top layer of a thin polyvinyl chloride film is laminated or fused to a non-slip bottom layer via a disposed interlayer of polyvinyl chloride plastisol. The non-slip bottom layer consists of a supporting non-woven fabric coated on both sides with a foamed plasticized polyvinyl chloride resin.
U.S. Patent Application Publication US 2003/0036323 Al by R. Aliabadi, published on Feb. 20, 2003, discloses a multilayered nonslip plastic shelf liner comprising an intermediate layer of fibrous polyester fabric enveloped by two thermally bonded layers of polyvinyl chloride. A thin coating of polyurethane is applied to the obverse side of the covering to provide a smooth frictionless surface, where the reverse side remains uncoated to impart nonslip properties to the laminated material.
None of the above inventions and patents, taken either individually or in combination, is seen to have solved the aforementioned problems associated with resizing removable, nonslip, non-adhesive surface coverings.
Accordingly, it is an object of the present invention to provide a removable, nonslip, non-adhesive covering sheet with an improved composite material having a grid of perforations to facilitate the convenient hand tearing of shelf, drawer or storage liners to size.
It is a further object of the invention to provide a removable, nonslip, non-adhesive covering sheet with a multilayered composite material having a top layer of polymeric film combined to a continuous bottom layer of unsupported calendered foam.
It is yet another object of the invention to provide a removable, nonslip, non-adhesive covering sheet having a top layer of polymeric film that reinforces the dimensional stability of the underling layer of unsupported calendered foam.
Finally, an object of the invention is to provide a removable, nonslip, non-adhesive covering sheet having an underling layer of unsupported calendered foam configured with a fine pattern of micro-embossed indentations to assist in the hand tearing of the material.
These and other objects of the invention will be apparent to those skilled in the art from the following detailed description of the preferred embodiments of the instant invention.